Hi,
thank you for the answer. Have you more details/pointers to explain
your opinion ?
If the HAAD is sent with RUT(Link1), is it an error ? or is it
compliant with the specification ?
Regards,
Nicolas
Vijay Devarapalli wrote:
> It should be the unicast source address of the RUT on Link0.
>
> But moving forward, when we revise RFC 3775, I think the anycast
> address should also be allowed to be used as the source address
> on the DHAAD reply message. There used to be a restriction earlier
> that an anycast address shouldn't be used as the source address,
> but was removed recently. I forget which spec.
>
> Vijay
>
> Nicolas Dichtel wrote:
>> Hi,
>>
>> I've a question about source address selection in HAAD Reply message.
>>
>> Here is the topology:
>>
>> MN1X
>> |
>> --------+-------+--------------- Link1X
>> |
>> R1
>> |
>> --------+-------+----------------------- Link1
>> |
>> RUT
>> |
>> - - - - + - - - - - - - - - - - - - - - Link0
>>
>>
>> RUT is a Home Agent and the Home Link is Link0. Let's call RUT(Link1)
>> the unicast address sets of the interface connected to Link1 and
>> RUT(Link0) the unicast address sets to the interface connected to Link0.
>>
>> MN1X sends a HAAD Request message to its home agent (RUT). The
>> destination address of this message is an anycast address. When RUT
>> sends the HAAD Reply message, which source address must be
>> used ? RUT(Link1) or RUT(Link0) ?
>>
>> RFC3775 Section 10.5 just says:
>> "A home agent receiving a
>> Home Agent Address Discovery Request message that serves this subnet
>> SHOULD return an ICMP Home Agent Address Discovery Reply message to
>> the mobile node with the Source Address of the Reply packet set to
>> one of the global unicast addresses of the home agent."
>>
>> Following RFC3484, I think that rules #5 (Prefer outgoing interface) in
>> Section 4 is reached. But, there is some cases, like for ICMP ECHO Reply
>> (RFC 4443 Section 4.2), where source address must be the destination
>> address of the request message. In our case, the destination address is
>> an anycast address (assigned to the interface attached to Link0) and,
>> following the RFC2526 Section 1, the packet is delivered to RUT(Link0):
>> "The anycast address may be assigned to one or more network interfaces
>> (typically on different nodes), with the network delivering each
>> packet addressed to this address to the "nearest" interface based on
>> the notion of "distance" determined by the routing protocols in use."
>>
>> So, it's not clear which source address must/can be used. For example,
>> the TAHI tests suite expects the use of RUT(Link0).
>>
>> Regards,
>> Nicolas
>>
>> _______________________________________________
>> Mip6 mailing list
>> Mip6@ietf.org
>> https://www1.ietf.org/mailman/listinfo/mip6
>